Fuji Electric Review
Vol.70-No.3,2024
Electric Distribution, Switching and Control Devices
Electric Distribution, Switching and Control Devices
For many years, Fuji Electric has been providing electric distribution and switching devices that enhance efficiency and safety in the use of electrical energy, as well as control devices used to automate and optimize production machine operations. In recent years, we have been working to reduce the size of our products and expand the application of thermoplastic resin in response to the need for reduced environmental impact. We will also showcase our electrical contact evaluation technology, which allows us to implement these improvements, and our efforts to improve simulation accuracy.
YAMANO, Yasushi
Current Status and Future Outlook
MORISHITA, Fumihiro; HATA, Junichiro; YAMAZAKI, Satoshi
Fuji Electric’s electric distribution, switching and control devices are key components that are used extensively in electric and mechanical equipment, playing an important role in a wide range of industries.We have been developing these devices so that they capture recent market requirements and trends.For our switching device line, we have developed the “SC-NEXT Series” with a focus on reduced size and energy efficiency to contribute to carbon neutrality.In low-voltage equipment, newly developed devices feature improved designs, simplified wiring work for greater labor efficiency, and safety features such as electric shock protection.As for high-voltage circuit breakers, we have developed products that contribute to reductions in environmental impact.In power monitoring devices, we are developing the “Breaker Measurement Unit,” which can be added on to existing breakers.We are vigorously working on the core technologies for creating new products, including development and improvement of electrical contacts, as well as simulation and evaluation technologies.
UCHIYAMA, Taku; TAKEMOTO, Takanori; SEKIYA, Masashi
Fuji Electric has launched the “SC-NEXT Series” for motors with rated capacities of 2.2 to 15kW as a series of successors to our conventional magnetic contactors. In response to recent demands to reduce environmental burdens, we have reduced the footprint by up to 40%, as well as saved power consumption by up to 73% as to DC models, expanding the range of rated capacities of motors to drive with PLC outputs without using control relays. Newly developing contact arrangement and optimizing the opening and closing mechanism of the contacts by effectively using transient phenomenon analyses, we have reduced the size and electrical durability as conventional models. We have also achieved the welding resistance against inrush current of the contacts to allow for the installation on the inverter primary side.
ONOGI, Yuma; NAKANO, Mikihisa; KUMAGAI, Akie
Fuji Electric has launched the “SC-NEXT Series” thermal overload relays to provide successors to our conventional models. Thermal overload relays are often combined with magnetic contactors in applications to protect motors from overload. To make thermal overload relays smaller in accordance with the magnetic contactors of the same series, which have been miniaturized in response to the recent demands arising in relation to reductions of environmental burdens, we have renewed the configuration of the heater element responsible for overcurrent detection. This series thus has higher rated currents with a frame size that is equivalent to that of the conventional models. We have also improved the structures and manufacturing methods of the mechanism of parts for opening and closing contacts and have applied a new factory adjustment method to reduce variations in operating characteristics, increasing overload detection accuracy.
TAKANO, Yoshihiro; KINOSHITA, Shunsuke
Fuji Electric’s φ16 and φ22 “Command Switch” series is a long-selling product line that was released more than 30 years ago. Machine tool manufacturers, who are also users, have come to require design factors in addition to conventional FQCD when it comes to Command Switches used in the operation panels of their products to increase value of the products. To meet these demands, we have carried out a model change with usability being thoroughly pursued and enhanced the lineup to satisfy new customer needs while simultaneously maintaining the operational feeling, which has been evaluated highly.
ISHIDO, Hideki
Fuji Electric has offered various optional accessories for its molded-case circuit breakers and earth leakage circuit breakers used in control panels for electrical equipment and electrical and mechanical devices to meet various requests for the additional functions of them. Our external operating handles, for example, deliver improved dustproof and waterproof performance, expanded non-protruding types to prevent erroneous operation, and a mechanism that allows the door panel to be opened even when the handle being locked. The terminal covers have achieved IP20 protection performance in all directions despite the easy installation. A mechanism for locking the handle of the circuit breaker main unit, which can additionally be installed, accommodates a wide range of locking devices such as padlocks to prevent erroneous operation and has increased strength to protect it from breakage.
SUDA, Hirofumi; TOKUNAGA, Yoshihide
High-voltage power receiving and distribution equipment uses insulating parts typically made from thermosetting resin, which provides high insulating capabilities and strength. Fuji Electric has studied the replacement of the material with thermoplastic resin, which allows for the reuse of waste generated in the manufacturing process and improves productivity with its shorter molding time. We have established a structure of our load break switch (LBS) that can secure creeping distance to ensure insulating performance despite the lower tracking resistance than thermosetting resin. We will expand the application of this technology to ensure a stable supply of resources and contribute to the stable supply of products by improving productivity.
TAGUCHI, Takahiro
Fuji Electric is developing the “Breaker Measurement Unit,” which serves to add monitoring functions to distribution components widely used in electrical and mechanical facilities. The device is designed to meet the requirements that involve visualizing the power consumption of each manufacturing facility, which is essential for visualizing the carbon footprint, and implementing preventive maintenance, which makes facility maintenance more efficient as a measure against labor shortages. Integrated with a breaker, the unit can be installed inside the panel to wirelessly collect data. In addition to the collection of basic data such as power quantities, it can sound precautionary alarm for overload and notify trip occurrences to facilitate preventive maintenance. We are verifying these effects through field tests undertaken at our factory.
IWAKURA, Tadahiro; MASUMORI, Kenta; SHOJI, Kazuki
Fuji Electric works on strengthening evaluation technology for electrical contacts to ensure high reliability and durability required for switching and control devices. Using a testing machine that simulates the contact operation of products, we evaluated the welding resistance and wear resistance of electrical contacts by ascertaining the relationship between the energy of arc discharge and the peeling force of the contact when the contact is opened, as well as the relationship between the cumulative arc energy and the amount of contact wear. Based on the relationship between the cumulative arc energy and the joint area of the contact, we determined the initial value of the joint area required to achieve our target in terms of switching durability. In addition, we performed electrical durability testing that conforms to IEC standards to verify the product’s switching durability by switching up to more than 2 million times.
HARA, Takatoshi; SHIZUKA, Takashi; OYAKE, Yoshiaki
During the product development of electric distribution and control devices, the use of simulations, which allow for the prediction of fatigue characteristics in a shorter span of time than would be the case with actual equipment, facilitates the early provision of highly reliable products. When developing the “SC-NEXT Series,” Fuji Electric used simulation to analyze the phenomena of fatigue fracture of members subjected to cyclic stress, wear of members that support the moving contacts due to sliding contact, and looseness of the fit of enclosure joints resulted from creep deformation. The simulation used physical property values obtained under conditions that reproduce the actual use of the products to improve the accuracy of analysis. The results of this were reflected upon the structural design to achieve the target of the product’s mechanical lifetime.
New Products
ISOTANI, Hitoshi; KITAGAWA, Shinji; OGAWA, Koji
The structural soundness of railway bridges built across rivers can deteriorate due to scouring and aging of the bridge pier foundation caused by rising water after heavy rains. If the scouring progresses, the piers will sink or tilt, greatly hindering train operations. For this reason, railway operators confirm structural soundness by conducting impulsive vibration tests in addition to visual inspections. However, enhanced labor efficiency and safety are required due to the time required and the danger involved in the work. To meet these requirements, Fuji Electric developed a bridge scour monitoring system capable of evaluating the structural soundness of bridges by monitoring micro vibrations of the bridge pier remotely and continuously.
TSURUSAKI, Yu; ISHIJIMA, Nao; KUZE, Naoki
To use renewable energy such as solar and wind power as main power sources, demand is increasing for large-scale electricity storage systems are needed to stabilize systems, which are needed to stabilize the power system. Fuji Electric has been providing power conditioning systems (PCSs) with storage batteries of 800V DC or less to date, but the product is being required to increases in capacity and DC voltage to reduce system costs. To meet such market demands, we developed the “PVI1500CJ-3/2750B,” a 1,500-V DC outdoor PCS with a large capacity (2,750kVA) with storage batteries.
